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Do you ask ATC for HILPT?
This specifically pertains to VOR approaches, but I guess it can apply anywhere else that has a hold in lieu of procedure turn (HILPT) also. There are numerous examples but let's try one: KUKI VOR-A.
If you were approaching from say the North (thus a teardrop entry is most suitable), does the hold constitute your course reversal, or must you conduct the procedure turn to get established for a simple ASEL? 5.3 miles out seems pretty good to get distance to get established, but maybe I'm missing something as an early instrument student? Do you have to contact ATC to let them know this is the way you'd conduct the reversal?

The hold on that chart is a dotted line, which means it's part of the missed approach. If it were in lieu of a procedure turn, it would be shown as a solid line. I believe the only course reversal shown on that chart is the procedure turn. ATC could just vector you to final, of course.

@Pondlife - You are very much correct. The hold in the example is for the missed approach procedure. Technically, there is not a hold to start the approach. One can be requested in order to gain time or lose altitude. But, it would be a separate request/clearance for the hold, then a request for the procedure. On the other hand, there is nothing stopping Saigafreak from only flying two miles outbound from ENI before starting their turn back onto the appropriate radial. Though, parallel & teardrop turns would be unorthodox.

Note the hold depicted is for the missed approach since it has dotted lines; a charted HILPT would be solid. That said, you can ask for nearly anything, and presumably ATC would grant it without requiring you to miss once first.

It would be nice if the body of the question had some content that would explain to non-instrument pilots what the acronym in the title actually stands for.  (Not ATC, but the other one.) Something about a procedure turn I suppose...

@Quiet Flyer - Yes, I am instrument rated and not sure about that one.  Thought it was an intersection, but it isn’t on the plate, and Stephen used it in the context of a published procedure turn...  Somebody?

@quietflyer I added the full name for a HILPT and a link to an article about them. It's a common abbreviation in the IFR world, at least in the US.

... at least among GA pilots who fly VOR approaches regularly.  (BTW, that isn’t intended to be snarky at all...). I recognize the term, but I am obviously not steeped in using that particular abbreviation and I have thousands of hours of IFR time.  (Albeit mostly military)

Typically, the way that it works in my local area is that the pilot would request the full procedure when wanting to use a course reversal. This would be interpreted by ATC to mean the pilot was going to fly direct to the IAF requested by the pilot when requesting the IAP. ATC would then vector the pilot in a manner to get the pilot to intercept the course at the most advantageous angle. The pilot may request to self vector, though. The pilot would then fly outbound on the IAP for the PT.
The PT has to be done along the outbound course. Though there is not a specific distance the pilot must fly in order to do the PT, it has to be flown in such a manner that the aircraft does not exceed a specific distance. The pilot can, however do the PT in as little a space as that provided by a hold.
If the pilot chooses to use the hold as a course reversal instead, they would request the hold first. They would follow that request up either with another radio call or within the same radio call with stating the intent of using the IAP to approach for a landing, touch and go, low approach, etc.
If the pilot does not make their intent clear when requesting the approach ATC will ask for the pilot to state their intentions. On a slow day, they may just ask you to report the FAF when inbound for a landing.
Remember though, the procedure for using an IAP would be to have your aircraft established on the lateral guidance, fully configured for a landing, at or prior to the FAF. That would preclude the possibility of flying directly to the FAF from any other angle or direction, then descending down for a landing. Because of that, ATC would be expecting you to do some type of course intercept or course reversal on the intermediate leg.

"ATC would then vector the pilot in a manner to get the pilot to intercept the course at the most advantageous angle." — not sure what you mean by this. If someone asks me for the full procedure starting at the IAF, I clear them direct the fix and let them figure out how to get aligned with the final approach course, in accordance with the FARs and the approach plate. I wouldn't vector them onto final approach course or any other kind of course. (Perhaps if I worked at a busier facility I would vector them toward the IAF before clearing them for the full approach.)

@randomhead - Thanks for your input from your ATC POV. That is my exact point. Unless the pilot asks for the full procedure, ATC has the leeway to vector the aircraft to be lined up with the lateral guidance of the runway. That usually means vectoring them to the Intermediate Leg of the procedure (usually between the IAF & FAF). Our controllers at the busy Class D airports out of which I fly take advantage of this a lot. They will vector the aircraft to the approach so that the time that aircraft has the approach tied up will be limited. Especially when the airspace is extremely busy.

@randomhead - As far as “most advantageous angle” ATC will Vector the pilot to intercept the course at less than a 90° (less than 90° of course correction to intercept) per AIM 5-4-3 & 5-4-6. It is also advantageous to ATC so that they may still control traffic separation.

I think I see what you mean: where you are ATC does vector onto the approach course, so that the pilot doesn't have the option of executing the full procedure (and tying up the airspace)? That makes sense, and that's where the 90º rule comes in to play—they have to intercept at 90º or less, or they have to be allowed to do a course-reversal maneuver, not both. I think we're on the same page.

In the case of an airport like KRWL, if I clear you direct FIKLA, I expect you to do a hold in lieu of procedure turn.

If I clear you direct FIKLA, I've put you on a random GNSS route, and I have to keep you in radar coverage until you get to FIKLA. For KRWL, this means keeping you at or above 12,000, which is almost 2000 feet above the start of the profile. You need that hold-in-lieu to get your aircraft down to an altitude that's safe for starting the descent profile.
Even if I could clear you down to 10100 (too much granite in the way), I'd expect you to make a hold-in-lieu at any angle over 90 degrees, and would protect the pattern. The only time I would not protect the pattern with a direct FIKLA routing would be if I specifically cleared you for a straight-in approach, which has its own conditions, including the GNSS radar requirements.
In KRWL's case, I would probably give you either the ARFEJ or CEXIT transitions (which also need 12000 on a random route), and let you get the aircraft down before FIKLA. Note that these are "NoPT" legs, so I will not protect the hold-in-lieu on the back end, only the route legs.


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Question on sUAS course in lieu of knowledge test for Part 61 certificate holders
If I am a PPL already, it appears that you can just take a course and pass a quiz to satisfy requirements for part 107 as such:
"If you are a part 61 pilot certificate holder and you have a current flight review (per 14 CFR part 61.56), successful completion of this course is your ONLY training and testing requirement. At the end of this course, complete the online knowledge check (exam) and print your completion certificate."
Now, I received my PPL in August 2019 and my IR on August 2020, and I know that both reset the clock on flight review requirements. However, since they specify flight review in the requirement, do I really need one or do the oral/checkrides for the ratings count as part of that review?

I’m not sure I understand what you’re asking. The title of your question doesn’t seem to match the body. Are you asking if the 107 requirement for a current flight review literally means a flight review, not a check ride or other equivalent activity listed in 61.56?

A rating checkride can be used in lieu of flight review (i.e. resets the 24 cal month clock) on part 61 for purposes of flying. Question is: does a recent rating qualify as a flight review in terms of getting a UAS certificate via the course rather than taking the knowledge test?

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What is the difference between Line-Replaceable Unit (LRU) and Line Replaceable Modules (LRM)?
i am studying Line-Replaceable Unit (LRU) and Line Replaceable Modules (LRM) but do not know the difference.

Related: What is the difference between Line-Replaceable Unit (LRU) and Integrated Modular Avionics (IMA)?

@DeltaLima Your related answer would answer this question if it clarified that LRMs are the replaceable components of the IMA.

@Gerry Thanks for the hint, I didn't realise I had answered that question. I've added the part about the LRMs. We can close this as a duplicate

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Why do NOTAMs consist of code instead of plain language?
I'm currently getting thru a PPL course book and I don't understand this. Is there any purpose of sending NOTAMs in this format:
"RWY 08R/26L DUE WIP NO CENTRELINE, TDZ OR SALS LIGHTING AVBL"
instead of plain language
"For runway 08/26, due to work in progress, there is no centreline, touchdown zone or simple approach lighting available"
Why do they force pilots to learn common ICAO abbreviations when they could simply send the text message without encoding it? The same questions goes for TAFs and METARs.

@mins automated processing of NOTAMs is still not common, AFAIK, that's why FAA/EUROCONTROL have proposed the DigiNotam standard

Related, some of the general comments about adoption and existing technology apply to NOTAMs too. It's also not obvious what "plain language" should mean, especially in an international, multi-lingual environment. Abbreviations and professional jargon in general tend to be precise and compact, even if they do require a learning curve. This isn't unique to aviation, of course.

@Pondlife
CAA could stop using the abbreviations. There's already enough "learning curves" in aviation to begin with, so why instead of writing "TDZ OR SALS", not simply write "touch down zone" and make it a standard phrase?

@ParadigmPilot I think this is getting off-topic for this site, but every professional activity I can think of uses a lot of abbreviations. They exist for a reason, after all, and aviation is no different from anything else.

In 1969 when I first started visiting my local airport weather bureau for flight briefings (yes, weather briefings were done in person by weather bureau personnel), it was a noisy place right after the turn of the hour what with all those teletypewriters clacking away printing the METARS, TAFS, and what not on to rolls of paper that collected on the floor behind each machine. Had it not been been for the abbreviations, I think it possible that they would not have completed one hour's reports before the next hour came.

You object to abbreviating "runway" to "rwy" but you happily say "I'm" and "don't". Some level of abbreviation actually improves communication. (Meanwhile, in the land of personal taste, I'd say that the NOTAM is excessively abbreviated but your "plain language" version is excessively verbose.)

They did not abbreviate CENTRELINE!

For the exact same reason you typed NOTAM instead of Notice to Airmen. Once you learn what NOTAM means, there's no need to spell it out, it's faster to type and to read. Additionally, I'm not a pilot, I've never even held a PPL course book to say anything of having read one, but, with a bit of basic reading about aviation (99% here), the only thing I did not understand in that line was SALS - it's not hard to pick up on the lingo.

The NOTAM format is from the time when people still would call the value of individual bits over a phone line.
Ok, that may not have happened, but my point is that data transfer was incredibly slow compared to current day standards. Therefore a compact format saved significant  transmission time and cost without losing any information. The format didn't change since.

why it's not changing?

@Electric Pilot: If it ain't broke, don't  fix it?  Everyone in aviation understands the current format: sswitching to a new one would cause confusion.

@ElectricPilot automated processing and generation of the messages for one thing. Ease of copying them out as shorthand while receiving them over the radio as well.

Abbreviations tend to be awkward over the phone. Over the telegraph and teletype on the other hand…

As I understand your question is mainly about line E of a NOTAM, right? Well, this one is in fact meant to use 'plain' English language, in contrast to all other lines, where location and reach as well as type and urgency and duration is encoded.
Just, as it already has been mentioned, NOTAMs originate in a time when transmission speed was unimaginable slow by todays standards. So the answer  is rather IT related ... stone age IT that is. Standard transmission speed back then was 45 Baud, that's 45 bit per second - with lots of pauses added for feed and other functions, resulting in an effective transmission speed of less than 8 characters per second (*1).
Already the lines before line E contain anywhere between 150 to 200 characters, thus requiring some 25 seconds to transmit. The E line you cite is another 60 characters, or 8 seconds. The suggestion made would now increase that to 129 characters or an additional 9 seconds. With no increase in information transmitted.
For a rough calculation it may be safe to assume 1 minute of transmission time per NOTAM. That's barley 60 per hour. And 60 is a rather low number of active NOTAMs within the reach of an aerodrome to be kept at hand for its pilots. Keep in mind, there was no internet and instant access to remote data bases at all. Everything had to be transmited ahead of time - and there where people collecting all incoming NOTAMs and filing them into folders (that's what line A supports) to be up to date and ready for flight planing.
So short message length was an essential must to make it transmitable.
It wasn't until the 1970s that the situation relaxed a bit due faster transmission - still not much, as at the same time air traffic, and related NOTAMs rose in number.
The other limit was introduced by early data processing. The E line is limited to 1200 characters at all. This (back then unimaginable hucht) limit was introduced by the size of disk block on the mainframe system used by. 2048 characters was the limit for a whole block, minus some organisational data, minus all other lines, this left 1200 bytes per NOTAM. Since some even needed more, block chaining for up to 12,000 characters was allowed - not realy liked though.
Bottom line, abbreviation was a must due the hardware available.
At the same time, these abrevations helped in understanding, the very same way we use extreme codified radio sequences for fast exchange and clear interaction. There is no doubt about the meaning, as every day language may create. This might seam strange, but it's like with any other formalized communication. No matter if its about debates in the commons or ATC communication - or in this case NOTAMs.

In the early 80s a 300 baud modem was quite standard, and 600 baud was screaming fast!

45 bits per second! That's fast! 31 baud is fairly common on ham radio. http://en.m.wikipedia.org/wiki/PSK31

1 - It's always been done that way.
2 - You'd be surprised how many government computer systems are still using ancient hardware and operating systems.

3 - no real need to except people wanting to be fancy.

and yes, I can attest to old systems remaining in use well past their sell-by date, not just in governments but any large organisation. Many are too large and central to business processes to replace without major effort.

There used to be a good technical reason (transmission time over low-rate modems), so everyone learned how to decode things.  That original reason has long since gone away, but nearly everyone affected has already learned the code, so the short-term benefits of changing are minimal--and accrue mainly to new entrants (who have little/no power) whereas the costs would be borne by everyone.
There's also a possible "hazing" effect: if the old timers had to go through something unpleasant, then it can become a ritual part of joining the tribe, regardless of what (if any) practical value it has to newbies.

Because the FAA imagines that we are still in the teletype age, and thus believes that every bit of text not actually burned into the the paper scroll (or perhaps we should say every byte of information not transmitted over the wires) is a precious saving of some sort.  It's exactly the same misguided reason that airport weather reports (METARS) are still formatted in the near-unintelligible condensed manner as they are.

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Why is the TORA of 27R not the same as the TORA of 09L?

09L and 27R are the same runway but just in opposite directions. I've drawn out a diagram and for some reason the TORA for 27R is 18m less? Where has that 18m disappeared? I've been trying to work out the difference in values using only the information in the table and I still feel that 27R should have a TORA of 3902m (the same as 09L).

Note that the numbers you have are not up to date. There is still a difference in the latest numbers, though.

These seem to be the numbers of Heathrow / EGLL. When you look at the taxi diagram, you see that on 09L you have a taxiway that places you right at the beginning of the runway whereas on 27R when taxiing on A1 you end up juuust behind the start of the runway – probably 18m behind it.


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Are taxi-way routing details saved?
I am currently working on taxi-way route optimization. Are there any systems that store the taxi routes taken by the aircraft either by hour or by day or by airplane?

Surface radar / A-SMGC data is stored, and will contain information about the taxi-routes, but not necessarily in a format that is easily accessible. What taxi route information are you looking for? Sequences of taxi ways, or just postion of the aircraft over a period of time?

Sequences of taxi ways

In modern A-SMGC systems with a routings service (manual or automated) the route will be digitally available and certainly logged. Such a routing service is necessary for driving automated taxi guidance (e.g. follow-the-greens). This is implemented only at a few airports, for example Incheon and Dubai. London Heathrow and Singapore have manual follow the green implementations, but I imagine they have some form of recording the instructed routings as well.

Your best bet will be to listen to recordings of taxi clearances issued by Ground Control.
The chance that you can see replays of enough ASDE-X or other surface radar recordings to get a meaningful data set is probably about zero unless you can get agreements with whatever ATC facility you're interested in.
While it's possible that some facility may record the data that you're asking about, the general answer is that the ground controller simply issues the clearance over the radio and the aircraft complies.  If a conflict arises that requires something different, then the controller issues a revised clearance & the aircraft follows the new instruction.  But unless a particular facility is doing something special (an extra person in the tower cab recording clearances & routings in order to undertake some specific analysis, for instance, or maybe a facility doing an analysis of ASDE-X tapes for some project), there's no widespread banking of that sort of thing.
Thus the suggestion that you will need to build your database yourself by listening to something like Live ATC (dot net) and copying down the routings given.


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What is Auto-thrust?
I have heard about auto-thrust yet I still don't know what it is. Can someone please explain to me what it is?
I know that I can just Google this up, but I was hoping that a community which revolves around aviation would be able to answer my question.
I did end up using Google to do some preliminary research and I found this definition:

An autothrottle (automatic throttle) allows a pilot to control the power setting of an aircraft's engines by specifying a desired flight characteristic, rather than manually controlling the fuel flow.

Related, but may be too specific: What are autothrust and manual thrust on an A320 (or other aircraft)?

In its basic form it's just like the cruise control in a car.

Autothrottle and Autothrust are one in the same.  Technically the latter is correct as jets don't have throttles.

In its basic form, it is just like the cruise control in a car.*
Here is a photo of the autopilot control panel on a Boeing 777. Note the "IAS 200" window on the left:

IAS stands for "indicated airspeed". When engaged, this setting tells the auto-thrust to adjust engine power to maintain 200 knots of airspeed.
Just like a car, when you go uphill you need more gas to maintain a constant speed, and when you go downhill you give it less gas. If the downhill is steep enough, you may have to use some brakes to maintain a constant speed.
Same thing happens when a plane pitches up to climb or pitches down to descend. Airspeed, vertical speed and engine power are closely related - changing any one will impact the remaining two. This is the fundamental of how planes fly, and likely your first ground school lesson if you learn to become a pilot. Auto-thrust is a component of the autopilot system which manages engine power. Note that I used constant airspeed as an example in the previous paragraph: advanced autopilots have many modes, and it can be set to maintain constant vertical speed instead of airspeed. But in all cases, auto-thrust manages engine power.
* Well said TomMcW

It is worth noting that many aircraft are not equipped with auto-thrust or auto-throttles, including many of those with sophisticated autopilots.

@JonathanWalters I wouldn't call those autopilots "sophisticated" then. And I'd say it's pretty common. Surely it is rare in GA, but on the passenger side, I'd bet at least 8 out of 10 flights you can book at major airlines is flown on an aircraft with auto-thrust.

I was thinking specifically of the Garmin GFC 700 as an example. I suppose there could be good reason to not call it sophisticated, but I would and others in the industry do.

@JonathanWalters the autopilot (and FMC) on Airbus and Boeing can do de-rated takeoffs, fuel economy management, descend energy management, auto-trim etc. I'd say these are the things that are missing, but then I agree many autopilots are very capable even without auto-throttle.

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Can thrust be produced only using the forward speed of a nozzle?
Why can't a nozzle that is already in relative motion to the air produce thrust by speeding up the air that passes through inside it?
So let's pretend you're in a glider with two converging nozzles (without fans or burning fuel), one attached to each wing. Shouldn't the air passing through speed up due to continuity, and provide a forward force on the plane?
Obviously this does not work in real life so I would like to know why. Is it because the bottom an top surfaces essentially function as a diffuser, which slow the air around?

Something has to provide the energy that is needed to accelerate the air.
In the simplest combustion engines this is the combustion heat. Air expands when heated and when the route out the back is the easiest to take, it will flow that way. More complicated engines use this heat energy to raise the pressure of the air inside the nozzle so there is excess pressure energy that can be converted into speed.
In your converging nozzle there is no excess energy available. In order to stream out the back, the air must have at least ambient pressure when leaving the nozzle. In order to speed up, the pressure ahead of the nozzle must be higher than ambient. But since the air enters the converging nozzle already with ambient pressure and flight speed, it cannot accelerate any more. Instead, the face of the nozzle will block all the air that will not fit through the smaller exit cross section, forcing it to flow around your nozzles. This is almost as effective for producing drag as putting a solid disk into the air stream.

It does not work for a couple of reasons.

friction on the surfaces creates extra drag
a diffuser will lower the pressure, and you're not adding energy to the stream. As a consequence the air going through the diffuser is not capable of overcoming the backpressure exerted by the sorrounding air, leading to a lot of turbulence and no thrust.

So you're left with a dead weight that increases drag and does not offer any benefit.
If it would work, you would have created energy from nothing, and perpetual motion machines cannot exist.


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What power have I obtained?
I am currently working on a question in aeronautical engineering. The question has asked me to provide the available power. I have calculated the drag, and am given the constant velocity. With that, I have calculated that into thrust. Upon using P=F*V, I have obtained a value.
Is this Brake or Available power for the engine?

If your airplane has a propeller or is a jet with installation losses, you need to consider propeller efficiency rsp. installation losses before arriving at the required engine power.

The drag that you have calculated for your plane is probably the drag at cruise velocity, straight and level flight. When you multiply it by the airspeed, the figure that you get is the net power required under those flight conditions. It would be exactly the same as the output engine power only if the propeller had an efficiency of 100%, converting all the engine output power into the 'wind power' that will produce the thrust reaction needed to push your plane. That's not the case in the real world, where props have efficiencies around 60-80%...

It will be the brake or available power for the engine only if the engine is running flat out at that speed. What you’ve calculated is the net power required to fly at that particular V.
Power available will be the max. power at that altitude, minus the power required you’ve calculated.

Neither, what you have calculated is the power state of the aircraft as Drag x Velocity at a given velocity.  This is power required to maintain steady state flight.  Units are kg x m$^2$/s$^3$ or kg x v$^2$/s.
Power output of an engine is literally fuel burn/s x the efficiency factor of the prop to produce thrust at a given airspeed.
We can see, at a given airspeed, thrust from engine = drag from aircraft.
One can reference power available performance graphs for a given aircraft to see at what airspeeds available power from engine exceeds the power state of the aircraft.  Maximum excess power is usually found at the airspeed corresponding to Vy.
Interestingly, with props, there is greatest excess thrust at lower airspeeds, but less power because V is smaller.  The aircraft can climb at a steeper angle, but at a lower airspeed.
"Brake horsepower" is the actual torque output of the engine at a given rpm.  It will equal the angular drag of the prop (units Force x distance/second).
"Available horsepower" is considered the maximum torque output at a given airspeed.  This value can be described as a (maximum) "brake horsepower" rating.


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Do Blue Angels jets have a snap-to-angle feature in their control sticks?
So, in most drafting/modelling software, we have a feature called Snap to Angle or Snap to Edge; its function is to snap the control(cursor) to the nearest most obvious angle/edge to relieve strain on operator to carefully move the cursor to that exact point.
If you haven't seen it try Right Click on Desktop > View > Align Icons to Grid & then move the icons around.
Now on to my question:
When performing the maneuver Opposing Knife Edge it is crucial that the roll angle (w.r.t. level) should be very close to ±90°.

Especially considering the high speed (& probably high G-Force) situations is a feature equivalent to CAD's Snap-to-Angle employed in air-show modified jets?

You seem to have a seperate question there at the end, if you could go ahead and put it in another question...that would be preferable.

Think about all the times snap-to doesn't do quite what you want. There's no place for a "feature" like that in a aerobatic fighter cockpit.

The closest you will get to this is the Airbus Control Laws I think.

Along Dimo414's line of thinking, pilots have a preference for being more in control of their aircraft, and are willing to pay a price in convenience.  In CAD, you are in charge of a few thousand dollar computer with an undo feature, so having the computer help is actually a really smart assistance feature.  In command of a multimillion dollar aircraft with one chance to do any given thing right, the less one is forced to trust the plane's computer, the happier they seem to be.

In reality, it is not that crucial to have exactly 90° roll for this manoeuvre. 2-3° won't make any visual difference, especially when viewed as on the photo. Meanwhile, any experienced pilot can hold the roll within 1-2°. Speed has little effect here, and G-force is not really great (probably even less than 1).

Short answer: No.
Long answer: No way!
This would be a feature which pilots would never accept and for good reasons.
There are many instances where you want to fly at a slight angle to exactly horizontal or vertical to make corrections. Just think of flying an approach with crosswind.
The designers have made the cockpit glazing transparent to enable the pilot to check and adjust his/her attitude, and this feature works really well. There is no need to add something which will be in the way of proper flying at some times.
What you do find sometimes on small aircraft with manual controls, however, is a trailing edge modification which helps with centering the rudder and/or the ailerons. See below for an example: This is the tail of the Klemm 35, and the rudder has two narrow strips which are deflected slightly to the left and the right, respectively. This increases the force gradient over deflection for the first few degrees when the rudder is moved away from its centered position.

Klemm 35 tail detail (own work)

"The designers have made the cockpit glazing transparent:" a wise choice (although that may change in the future).

Thanks man and sorry if I provoked anything wrong. Just wish I could enroll in Blue Angels someday . . .

I can't speak for the Blue Angels, but there are some airplanes that have this feature: those equipped with a DFC100 autopilot.

Its difficult to see how this feature could ever work, because you move the stick to move the wings, and then centralise it again to stop the roll. I am sure though it would never be quite central, small adjustments would have to be made all the time to make the flight path accurate and the aircraft might be overbanking or under banking depending on its attitude for example. So its truly pilot skill you are seeing when you watch the Blues and long may it continue this way!

This is what I tried to say in my comment to @TUMBLEWEED. Aircraft is generally controlled by angle rates rather than angles, in roll especially. In a dynamic environment such as a flying aircraft, such first-derivative control was shown to be nearly ideal for humans. That said, there are autopilots/control systems that 'snap' to certain angles or simulate direct angle control in some specific scenarios.


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Can I fly a STAR (standard terminal arrival route) if I can't maintain the minimum speed for it?
I fly a single-engine airplane not capable of more than 120 KIAS. I'd love to fly a STAR (standard terminal arrival route) into my local airport (US), but want to make sure I fully understand the STAR procedure.
Most of these STARS I'm looking at flying are RNAV stars with "expect" altitudes, which I understand fully, but have published speed segments of around 250 to 210kts. It's my understanding that if I'm cleared for the arrival "cleared the Tops 5" I'm to follow published speeds and lateral guidance and the altitudes I'm given.
Is there ever a case I could fly a STAR and not have to follow published speeds or is it implied when flying the STAR? If my understanding is correct, I wouldn't be able to fly a STAR with published speeds if I can't meet them?
Could I file for a STAR in my flight plan and not get whacked with a pilot deviation if I'm cleared for the arrival and can't meet the speeds. I would think I couldn't fly them if I can't meet the speeds, but want to make sure I'm not missing something.

What is your "local airport'? Permission to fly a STAR at lower-than-published airspeeds may be possible in a quiet regional airport during non-peak hours, but something busier like ORD or SEA would be shot down long before you even got off the ground. You really don't want to get run over by an airliner doing published speeds, and airports aren't going to let you jam up a standard route.

Welcome to aviation.SE! I think you're asking about the US, so I added the FAA regulations tag. If you're asking about rules or regulations, please always tell us which country or regulations you're asking about.

Apologies, the local airport is in the US, a relatively large charlie.

According to the FAA's Instrument Procedures Handbook, chapter 3 (p. 3-16):

Pilots may have noticed that minimum crossing altitudes and airspeed
restrictions appear on some STARs. These expected altitudes and
airspeeds are not part of the clearance until ATC includes them
verbally. A STAR is simply a published routing; it does not have the
force of a clearance until issued specifically by ATC. For example, minimum en route
altitude (MEAs) printed on STARs are not valid unless stated
within an ATC clearance or in cases of lost communication.

So unless ATC explicitly, verbally assigns you a minimum airspeed, you don't have to maintain it. If they do assign one and you can't maintain it, you can simply say "unable" and request to fly it at a lower airspeed. If ATC can't allow that for some reason (like spacing) then they'll likely vector you instead.
That means that if you are simply cleared for the STAR with no specific airspeed it's not a pilot deviation to fly it more slowly than the airspeed on the procedure.
I have no idea how likely or not it is that ATC would allow you to fly the STAR you have in mind. That would depend heavily on traffic, and things could change at any time.

It makes sense that the alt restrictions are effectively only there for lost comms, but a speed restriction seems completely redundant; if you're lost comms and can't meet the min speed, you can't meet the min speed so what's the point of having it.

Thanks, Pondlife. I actually just read that exact excerpt from the IPH the other day and that's what completely confused me. It seems straight forward from reading it but I've always been told if there are charted speeds and altitudes that you must be able to meet them to fly the star. Reading boldmethod and the IPH did nothing but confuse me, so I appreciate the clarification.

If you’re flying low and slow, in practice you’re not going to spend much time on a SID or STAR unless you lose comms. ATC would rather vector one plane (you) off the procedure so the dozen jets and turboprops behind you going twice as fast can stay on it.
Traffic is light enough now (late 2020) that if you specifically tell them you want it for the practice, you may actually get to stay on the routing—but with lower speeds and altitudes that you can actually achieve.
The key to avoiding a pilot deviation here is to not accept any instruction or restriction you aren’t capable of obeying. Just tell them “unable” if that happens and offer what you can do, and they’ll find a way to make it work. Don’t parrot what they say and then think about whether you can actually do it!


text:
What Transponder code to use flying between Oakland and Hawaii?
Where to find the appropriate Transponder code for crossing the Pacific?

I read this question as "what is a transponder code?"

Do you want to attempt a VFR fly over the pacific?

Flying IFR, or VFR?

Whichever code is assigned to the individual flight by ATC. There isn't a fixed code to use for any one specific route. You might want to see: How does ATC know if you have been assigned a squawk or not?

IFR flights outside radar coverage will typically be told to squawk 2000, in contrast with VFR flights that will be squawking 7000 or 1200. Upon reaching radar coverage again, they will be given a new discrete code.

These are not, however, pacific specific (how poetic).

It's mostly to have them broadcasting for TCAS purposes.

@JohnK ... without conflicting with any discrete code that might already be in use on any side of the non-radar area. It also serves as a visible reminder to the receiving side that the aircraft needs a discrete code once it shows up on their scope.


text:
European aircraft liveries list
We live few miles away of an airport and we see a lot of departures and I would like a tool to enable my 7 year old daughter to recognize the company from the livery.
Is there a pdf or anything else (printable) with the list of the main airlines that fly in Europe with their liveries?
The best would be with some pictures (or even drawings) of their most common aircraft seen by different angles.
We live in northern Italy by the way (near MXP/LIMC) if there is a list for those who fly in Italy.

I just want to say that I think this is a lovely idea. My 3-year old daughter frequently asks me to open my flight-radar app to check where an aircraft is coming from/going to, so I can very much relate to this. Be careful though, I got my first aircraft book (including a chapter full of pictures of liveries of airlines from around the world) when I was 8 years old and I have been hooked to aviation since :-). Over time it got so bad that I even ended up moderating this site!

This is really a three part question, I'll try to answer it appropriately
What airlines fly into Milan Malpensa airport (MXP/LIMC)
The first place I'd start is the arrival and departure info for the airport itself. A quick glance shows the usual european low-cost operators (EasyJet, Wizz & Ryanair) as well as the larger operators (Emirates, British Airways, American, Singapore, Air China, Lufthansa, Cathay Pacific and of course, Alitalia!).
You can also check out the airport's wiki page which has a helpful section on Airlines and destinations served by the airport (direct link).
What do the liveries of specific airlines look like
I'm not sure you'll find a single handy pdf with all these on, but again wikipedia has some helpful information - indeed a specific list of airline liveries and logos. Cross reference this list with the one above and you could pull together a helpful cheat-sheet of all the ones which fly into LIMC.
How do I identify different types of airliner
Thankfully, the list of commonly used airframes is reasonably small, unfortunately with quite a fair number of variants of the same model if you're trying to be exact.
Once again, wikipedia will give you information about each of your chosen airline's fleet, and you can check arrivals and departures on something like flightradar24 to see which aircraft are flying which route.
There are websites dedicated to the art of identifying commercial airliners such as airlinespotter.com and aircraftrecognitionguide.com.


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Here's another German aircraft of unknown descent?
A most unusual all-white single-engine pusher tri-plane

Siemens-Schuckert DDr.I (just use Google Image search) https://lens.google.com/search?ep=gsbubb&hl=en-CA&re=df&p=AbrfA8raPmLx37JEbrXCvYxQzzK9WDAtKCeHrm_fI4y_HqeP7cYS83HqPE8H7EtSM0e11sdTVUYa7p6wqPdV9CPiHJEWJmP6e3tcIsWaON7sNkxgeF6lKnosPV_SeVfuJzolIZ9H8hhAaJve52S20lW-0tALyNZtjJjq2DtvZWsXUltM6363QYXJ07cSVSbFM51h2Uz65ZLHhy_sjA%3D%3D#lns=W251bGwsbnVsbCxudWxsLG51bGwsbnVsbCxudWxsLG51bGwsIkVrY0tKRGswWXpReFkySmhMVEppTjJRdE5EYzFaaTA0TjJNeExXSTBOR05sTldGbFlXWXlNeElmYnpKdlNqZGpVRzFWTXpSa1ZVTm1hVWxtYTFwaVJFTmtaM1owT1hab1p3PT0iLG51bGwsbnVsbCxudWxsLDEsbnVsbCxbbnVsbCxudWxsLFswLDAsMTAwMDAwLDEwMDAwMF1dXQ==

I don't get the downwote here...

@sophit: That picture is the one from the Wikipedia page for that airplane. Takes about 0.5 seconds to find using Google Image Search. "does not show any research effort" seems to apply. (Note: I didn't downvote, but I would understand how someone could consider that insufficient research. Especially since this is the second Wikipedia picture identification request within 70 minutes.)

This is Siemens-Schuckert DDr.I

a World War I German twin engine, push-pull configuration triplane
fighter aircraft. Only one was built, crashing on its first flight.

Your picture is used on the Wikipedia page, it's not too hard to find with image search!
Here's what happened to it (source)

Many thanks - much appreciated.


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Why are podded engines preferred over engines fitted inside the fuselage or wing?
Given the fact that podded engines on the wings of airplanes cause much drag (and thereby contribute to a lot of loss of efficiency), why do airliners still prefer podded turbojet engines over turbojet engines fitted inside the fuselage (or inside the wing) ?
Edit
This question is not regarding "What is the role of Pylons in a podded jet engine", but this is about "Why podded engines in the first place?"

Who says engines cause drag? For me, they create thrust (if they run), quite the opposite. Placing faired engines in the free flow gives them the best efficiency, again quite the opposite of what you claim. See here for the answer. Buried engines have higher losses due to distortions in the intake flow and long exhaust tubes.

What about engines placed inside the wings (contrary to the engines below the wings)

Efficient engines need much air to work with, and are consequently too big to fit inside a wing.

Have a look at this link : http://en.wikipedia.org/wiki/De_Havilland_Comet

possible duplicate of Why do we use pylons to mount engine on jet airliners?

Nopes, that question deals with whats the use of pylons for mounting podded engines, my question is regarding why do we go for podded engines in the first place?

Let us continue this discussion in chat.

Ad Comet: It was construction nightmare (the wing root carries all the weight of the aircraft), maintenance nightmare (engines need lot of maintenance and sometimes replacing), horribly noisy (no structure that could damp vibrations between engines and cabin) and the wings are not thick enough to host modern high-bypass turbofans anyway.

^^ This should be in the answer I guess

I think the first Peter's comment is better answer. Maybe combination of the two should be.

Then post it as an answer, so that I can accept if its good enough. Also, from the community point of view, no one searches for answers in the comments

Using a design with a swept wing and an unswept tail as a reference for aerodynamic quality is ridiculous. Those guys at deHavilland were clearly outside the scope of their competences when they designed the Comet.

How is unswept tail disadvantageous while using a swept wing? Or you want me to post this as a separate question?

Most important factor affecting drag is frontal area. Almost all frontal area of the engine pod is the intake and it has to have the size it does to collect the air the engine needs. So there is not so much drag to be saved.
Beside that, embedding the engine in wing roots like De Havilland Comet did has many disadvantages, most of which also apply to the central engine of three-engined jets (B727, DC-10):

The wing root carries the weight of the aircraft, so weakening it by embedding the engine is design and construction complication.
Access for maintenance is difficult. Engines need a lot of maintenance and sometimes need to be replaced.
Uncontained failure is more dangerous (see UA232).
There is not much structure to damp vibration, so it is awfully noisy.
And last but not least, modern high-bypass turbofans are huge. They would not fit in the wing anyway.

And reasons for not attaching the engines directly to the fuselage or wing are already mentined in Why do we use pylons to mount the engines on jetliners?. Mainly, the inlet needs:

Free space around it from which it can draw air at slow speed.
Free space around it to which it can spill the excess air at high speed.

And the engines mounted forward of wing actually improve the distribution of cross-sectional area according to the Whitcomb area rule and they dampen flutter, so the wing can be slightly less stiff and thus slightly lighter.


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What are the rules for close/formation flying of civilian planes?
Two recent questions and their answers have raised a further question.
In Are there laws about how close military aircraft can fly to passenger jets, and are they enforced?, we learned that "the military can get as close to other aircraft as they damn well please, through a procedure called Military Assumes Responsibility for Seperation of Aircraft, or MARSA".
In Why are there NASA branded F/A-18s? we see a picture of closely flying planes, and a comment notes "NASA is a civilian agency".
Do the NASA planes fly under MARSA rules or another set of rules for civilian agencies?  Are there other non-military agencies that fall under this rule too?

Pilots are allowed to fly as close as they want to each other as long as all parties agree to it and feel safe doing so.
Air Traffic Control cannot guarantee separation for planes in formation flight,So this will only be done under VFR and in VMC, where pilots can maintain visual separation from each other.
Many stunt fliers are civilian pilots and will routinely fly in close formation as well.
Other notable example of civilian formation flight include Mythbusters testing airplane fuel efficiency in formation and Airbus' publicity stunt with 5 A350s

Stunt flying didn't even cross my mind when I wrote this question - makes perfect sense, thanks :)

note that military planes flying information will do so in IMC. the lead plane has the xponder code, and the other planes turn off their transponders. the followers need only be able to see each other.

You already have a good answer on separation specifically, but it's worth noting that there are a few general rules about formation flights in 14 CFR 91:
The most specific formation rules are in 91.111:

§91.111   Operating near other aircraft.
(a) No person may operate an aircraft so close to another aircraft as
  to create a collision hazard.
(b) No person may operate an aircraft in formation flight except by
  arrangement with the pilot in command of each aircraft in the
  formation.
(c) No person may operate an aircraft, carrying passengers for hire,
  in formation flight.

Charity flights are exempt from air carrier (part 119) and drug/alcohol testing (part 120) requirements, but only if the flight is not a formation flight (among other conditions):

§91.146   Passenger-carrying flights for the benefit of a charitable,
  nonprofit, or community event.
[...]
(4) The flight is not an aerobatic or a formation flight;

You must provide formation details if you're filing a VFR flight plan:

§91.153   VFR flight plan: Information required.
(a) Information required. Unless otherwise authorized by ATC, each
  person filing a VFR flight plan shall include in it the following
  information:
[...]
(2) The type of the aircraft or, in the case of a formation flight,
  the type of each aircraft and the number of aircraft in the formation.
(3) The full name and address of the pilot in command or, in the case
  of a formation flight, the formation commander.

recheck that middle one. they are mostly exempt from xyz unless they are flying in formation. here's the part you omitted: "are not subject to the certification requirements of part 119 or the drug and alcohol testing requirements in part 120 of this chapter, provided the following conditions are satisfied"

@erich Your interpretation is more legally precise, but for practical purposes "You may not carry a passenger in formation flights if it's a charity event" is probably close enough (because if you do operate in a formation flight the magic exemption from Part 119 goes away, and most folks aren't going to go get an air carrier certificate just so they can go fly Young Eagles or a local fundraiser group in formation).

@erich I updated it to clarify that point

Why are we even discussing the exemption for charity events?  The question is about formation flying, and it simply can't be done on charity events.  It sort of distracts from the actual question / answer.  Also, I know that the regulation states it, but if you are going to call out the charity portion specifically, then it is a pretty important point that formation flying isn't allowed on commercial flights.


text:
How does the pilot check if an engine fire is real?
I've read this question and its answers basically asking why putting out an engine fire is not left to the computer but a manual task.
One of the points mentioned is that there simply might be a sensor error or similar and the engine isn't actually on fire, in which case you obviously don't want the computer to needlessly shut down an engine.
My question however is, how do the pilots assess wether the engine is actually on fire or not?
All planes I've been on had their engines very close to the aircraft and I doubt they are easily if at all visible from the flight deck. I would assume a good indicator might be the loss of thrust, but that could also be detectable by a computer. Do the pilots have cameras they can activate to check on the engines, or do they call the cabin personal and ask them to take a peek, do they walk out and check or is it based on how loud the passengers scream in the back? I guess all of these work, but what is the common procedure?

I quite surprises me that the modem aircraft don,t have cameras so the pilots can visually check the out side of the aircraft and jet engines. I only say that because of my viewing of the Air Crash Investigation TV program. There seems to be a lot of occasions that despite the instrument readouts the pilots make a wrong decision.
Such as flight LL1862 to Amsterdam here the pilots did not know that both engines had fallen of there left wing.

"How does the pilot check if an engine fire is real?"  Umm, open the window and stick your head out to look?

@dalearn: And you do that how, exactly, when at FL 350 and cruising at around 1000 kph?

@Sean Very carefully.

Engine fire implies that there is a strong heat source (commonly a fire, but could be a hot substance) in a location there should not be, usually around the outside of the engine.

Engine fires do not necessarily need to be connected with a loss of thrust.
Visually, they are pretty diverse- there may be smoke, there may be little smoke (aside from that, what would you do at night?).

The general rule is to treat the cockpit instrument indications as real every time. You do not need a visual confirmation.
You would rather take safe action a thousands times too many than one time too little. The aircraft is designed to fly on one engine and it's probably one of the most common exercises for pilots in simulators.
You are correct that sensors do get it wrong. Here is a very recent incident that involved just that. The reason for the sensor discussion is that a decision is only as good as the information you can base it on, and a human is generally a better decision maker than a computer as it currently stands. Take this very complicated and confusing situation for instance- how would a computer decide and respond?
There is no physical damage in hitting the fire button which will shut the engine down. Discharging the Halon fire agents would normally require a new bottle. It is a bit of a 'hard' engine shutdown: it cuts fuel, bleed air, electricity and hydraulics. If the fire warning (i.e. heat source) persists, you generally escalate it to discharging fire agents, although in most cases shutting the engine off is a sufficient measure.

That makes much more sense than what I thought the answer implied. Thanks for such a thorough answer :)

In the planes I've flown, the only damage from discharging the fire bottle is, that the bottle has to be replaced.  That said, while we have no problem letting a computer shut down the APU when there is a fire indication, the risk of the computer going nuts (not false indication, but bad processing) is enough that we don't entrust it with such a critical step.  Maybe I just hit lotsa birds, and the difference between landing or crashing is keeping the only running motor still on, even if burning, for another 30 seconds before I shut it down. My call, not a computer's.

@RalphJ after some research I am indeed wrong. I stood under the strong impression that you injected a load of powerful chemicals (powder/foam) into the space.


text:
Should the type of plane influence my travel choice?
With those many websites that compare flights we usually have the opportunity to chose between different paths to reach the final destination.
Should the type of plane influence the decision? Ex. If I see that one company uses a Boeing 787 instead of a Boeing 767 or an Airbus A330-300, does that influence the travel experience in a perceivable way (In terms of turbulence attenuance, noise reduction, smoothness of flight, different types of landing/take off)?

What is mean by "etc"? Because that makes the question somewhat broad.

I feel that most of what you are wondering about has to do with creature comforts (seats, ride quality, storage, etc).  I think you would be better served on Travel.SE or a travel forum (where I've seen a lots of discussions on this very topic).  We tend to discuss aircraft either on an operational or design level, and I don't think either of those apply to what you are asking.

I would vote to move this to Travel.SE as well.  Our help page says questions regarding "The 'passenger aspects' of commercial air travel... can be asked on the Travel Stack Exchange site".  People on here can debate how a plane flies well most of those considerations are for the pilot, not the passenger.  See http://travel.stackexchange.com/questions/28978/which-airplane-is-the-safest or http://travel.stackexchange.com/questions/3711/when-i-have-the-choice-should-i-choose-traveling-on-an-airbus-340-330-or-a-boein

As a general rule, not really, though there may be some factors that could cause you to consider it as part of your decision-making.

Some short-haul routes may be served by aircraft of significantly different sizes. For instance, some flights between San Francisco and Los Angeles may be on a Boeing 737, while others are on a CRJ Regional Jet. Still others may be offered on a turboprop like the Dash 8 or the even smaller Beechcraft 1900 (or even smaller aircraft, especially serving remote areas). Even those who aren't afraid of flying may be uncomfortable on small "puddle jumper" aircraft, as the seats and headroom are usually physically small and they can be more impacted by turbulence. Such aircraft can also require standard carry-on bags to be checked at the gate (they are usually returned to you at the gate on arrival), as lack large overhead bins.
The Boeing 787 Dreamliner can be pressurized to a lower cabin altitude and has a higher level of humidity than is typical. Efforts were made to lower cabin noise as well. This can lead to a more comfortable flight. Many of these enhancements may be carried over into future next-generation aircraft.
There may be differences in the cabins depending on the aircraft model, especially in premium classes. For instance, first class passengers on Lufthansa may have a separate bed on Boeing 747 aircraft, while those on Lufthansa's A340 will have to make do with sleeping on bedding atop their luxurious seat. Emirates business class is supposedly far better on the A380 (which includes a bar in the back) than the 777, though which you get mostly depends on your route. In other cases, an airline may be rolling out a new premium seat design, which is only available on some aircraft types. While the differences are less pronounced in economy, there may be variations in seat pitch (legroom) and configuration (2-5-2 vs 3-4-3 for example) that can make a significant difference in comfort.
Some people prefer newer aircraft. This can be difficult to guarantee by type alone though, as many aircraft have been produced over a period of decades. Even older aircraft have to go through a rigorous inspection and maintenance procedure though.

That said, most people are choosing their flights based on factors like price, route/time, and frequent flyer membership. Type of aircraft is usually pretty low on the priority list unless you're an enthusiast determined to fly a certain new model.
Also note that aircraft type is never guaranteed, and carriers reserve the right to make substitutions for operational reasons without notice.

Or a rare model -- I'd love to get a chance to fly on an Il-96 or a SSJ-100 because you just don't get the opportunity all that often!

@UnrecognizedFallingObject True. And while most travelers are not inclined to care very much, an unusually high percentage of the people here and on Travel.SE are those sorts of people. :)


text:
If an accident were to occur at a cross-border airport, who would investigate?
In the Wikipedia article Canada–United States border, there are several airports mentioned where the airport straddles the US-Canada border, in some cases the runway even being partially in the United States and partially in Canada.
If there was an accident at one of those airports, what agency would investigate the accident (i.e. the NTSB or the Canadian equivalent (the TSB?))
I'm specifically thinking of an accident that might have begun on one side (such as hitting the runway too hard on touchdown, or a botched approach), and led to something happening on the other side (such as an overrun, or a loss of control on the runway).

Probably both in a joint investigation, or even more if it is a foreign airline (for example an European airline the CAA would also investigate). Even more if there are other foreign nationals the countries of their citizenship may also request to investigate. Additionally if foul play is involved it could get the FBI or Interpol in the mix.

@RonBeyer I'm sure it would be a joint investigation, however even still I'd imagine there has to be one agency in charge.

Maybe, maybe not. It wouldn't be the first time multiple agencies were involved and issued conflicting reports.

And where do you bury the survivors?

@WayneConrad I'm not sure why that is a question, almost always the bodies/remains are returned to the country of origin and families for burial.

@RonBeyer I apologize, I was alluding to an old trick question.  The punch line is that you don't bury survivors.

@Wayne, Beat me to it!! And if a rooster lays an egg right on the crest of a building oriented directly east-west, which way will it roll down, to the North, or to the south?

@RonBeyer Next question, what happens in that situation if the accident aircraft is an Embraer operated by that European airline but the aircraft is registered in Australia? This can get messy real quick...

@WayneConrad You do eventually. Typically, at least. However, in such a case it's normally unrelated to aviation.

By ICAO conventions, the lead investigator is the country in which the accident/incident occurs, unless otherwise delegated. This is fairly common: for example an engine fails in Canadian airspace but they divert to Iceland, it's initially Canada's responsibility.
So you have an argument for whatever country the airplane hit the ground first in your example of a hard landing.
Additionally, ICAO Annex 13 recommends that if the country can't be decided, the state of registry should conduct the investigation:

5.3 When the location of the accident or the serious incident cannot definitely be established as being in the territory of any State, the State of Registry shall institute and conduct any necessary investigation of the accident or serious incident. However, it may delegate the whole or any part of the investigation to another State by mutual arrangement and consent.

Practically, I would imagine they would delegate the investigation to the country of registry of the aircraft, since that's where the tax dollars were paid.


text:
Do the A220's controls have force feedback for dual pilot inputs?
Airbus's 3x0 series designs have often been criticized following incidents and accidents over the relative lack of haptic feedback on the control sticks. Dual input conditions give a visual (and aural?) indication, but no physical indication, unlike on aircraft with mechanically linked yokes. This is believed to have played a role in the crash of Air France 447, for instance.
When Bombardier designed the C-Series 300, which is now manufactured and sold as the Airbus A220, did they match Airbus's practice, or add additional physical feedback that would make it different from the rest of Airbus's product line?

Related: Could sidesticks be linked?

A220 cockpit
Image source
A320Neo cockpit
Image source
The Airbus A220 started life as the Bombardier C-series, with the two companies starting a partnership in 2018. An article about the C-series flight controls mentions the following:

Flight control
C Series is a Fly By Wire (FBW) aircraft with a passive side stick controller, very much like an Airbus. As discovered during my A350 flight, this is OK. Active feedback sidesticks would have been better, but they were not available to the C Series project.
The throttles are like Boeing throttles; they are back-driven, i.e., one can see and feel when the auto throttle is working, which is good. This is typical of the C Series.

Passive side sticks, same concept as that of the Airbus designed A>320 families. Passive meaning: the stick can be deflected by hand forces only, and when doing so only the feedback spring forces can be felt. And indeed it would give intuitive feedback of what the other pilot is doing if the sticks were mechanically coupled, or if each stick would contain a back-drive electromotor that feeds from the position input of the other stick. As mentioned in this earlier answer:

The Airbus side stick is ... a stick loaded by a passive spring force sending back position signals. It had to be that way in the 90s when the sticks were designed, although we were already running digital force loops in real time @ 5000 Hz on a Motorola 68020, and had the technology to couple two (active) sticks in software. Did it for Mercedes and for quite a few simulators, but sadly not for Airbus.
So how it could for instance be implemented for the A320 side stick: program the passive forces that are there now for normal operation but always couple the sticks, program a stick pusher for when in alternate law and stalling, and leave the current override button solution in for when the Control Loading System fails. We were part of an aircraft company then and making the system airworthy would not have been a problem.


text:
What are the types of NOTAMs and how do USA NOTAMs differ from the ICAO definitions?
I'm looking for a complete list of the types of NOTAMs that can be found in the USA and under the ICAO definition. I looked at this question and it gives me a good starting point, but I'm not clear on how NOTAMs vary between the USA and when ICAO is used. Or maybe the USA is using "the ICAO way."
Is there a document that could help me compare where there is overlap and where there is a difference between how NOTAMs are defined in the USA and internationally. I assume there are ICAO definitions for NOTAMs that are used internationally.
If there are specific definitions for NOTAMs for countries other than the USA, that would fall outside the scope of my question here but might be an interesting additional subject matter for a very thorough answer.

I'm voting to close this as too broad, because comparing US to "International" encompasses up to 194 different answers, and a minimum of dozens of answers. The world is not divided into "US" and "Not US", and the US does not vary from ICAO definitions any more or less than any other country. Needless to say, most countries have their own NOTAM definitions, although they broadly come into two categories: Aerodrome, and local/area.

@JonStory I addressed your concern about the broadness. I just want the answer in terms of the USA and ICAO. That's two sets of criteria. What do you think?

I've retracted my close vote, as I feel this is now an answerable question

There are significant differences between US domestic NOTAMs and international NOTAMs, please note that US NOTAM Office issues NOTAMs in both formats (NOTAMs susceptible to affect international flights being issued in international format). Canada is also issuing domestic NOTAMs in the same format than US.

encoding is different, US domestic encoding is described in FAA order 7930.2R (https://www.faa.gov/documentLibrary/media/Order/7930.2R_basic_dtd_1_5_17_(2).pdf), international NOTAM encoding is defined by ICAO doc 84000
Domestic NOTAMs are mainly split between D NOTAMs (about airports and navigation facilities) and FDC NOTAMs (about airspace, procedures or regulations), there are also military NOTAMs with more subtypes.
there is to my knowledge no document describing in detail all differences between both encodings, although the FAA order 7930.2R is quite detailed and provide information on both types and some list of differences.
other documents are useful, for example https://www.faa.gov/documentLibrary/media/Advisory_Circular/150-5200-28F.pdf that provides guidance on using the NOTAM system for reporting airport facilities changes or outages and for
utilizing the Runway Condition Assessment Matrix for airport condition reporting

There are many differences between both formats, for example:

domestic NOTAMs are easily recognized as they start with an exclamation point !
the international NOTAM encoding is more structured. For example, a Q field will summarize essential NOTAM information, including affected FIR, vertical boundaries, geographic coordinates. In US NOTAM, geographic coordinates is described in the text of the NOTAM and then less easily decoded automatically.
the Q code also store the type of affected facility and the state of the facility. US encoding for facility types is different.
domestic NOTAMs are using standardized phrases defined in FAA document but not recognized by ICAO standard, the FAA order 7930.2R list them.


text:
Should an IFR-certified radio's automated nav aid identification feature be considered positive identification?
Should an IFR-certified radio's automated nav aid identification feature be considered positive identification? Should manual identification still be performed? Does anyone know if this is addressed in any FAA regulation or publication?
An example of automated identification is found on the Garmin 430. When a nav aid is tuned automated identification takes place and the result is annunciated visually.

This strikes me as a very odd question. If the G430 is FAA certified, then I would think that it would have been determined to be trustworthy through a long and expensive process. Of course, the FAA is staffed by people, and people can (and do) make mistakes. Is there something that leads you to believe that it isn't trustworthy?

This question has been discussed a couple of times on the AOPA forums (members only) and the conclusion there was that it's completely fine to trust the automated identification. If the system is fully certified for IFR then why wouldn't you trust it? And if you don't trust one specific feature then why should you trust any of them?
Identifying NAVAIDs correctly is in the instrument PTS but the FAA doesn't require any specific method of checking. In my last instrument checkride I used a G1000 and the DPE had no problem with me using the automatic identification; that's what it's there for.
Having said all that, things can and do go wrong, so cross-checking against other sources is still a good idea. For example, when you load a VOR approach from the database, the G1000 will automatically tune NAV1 to the NAVAID frequency and identify it. If either the frequency or the name doesn't match what's on the approach plate - or if the name is missing because it couldn't be identified - then something is wrong and you need to investigate.
Ultimately I think this is a question of comfort level, both personally and with the equipment. Some people will check the morse ID directly every time, out of habit or preference. Others won't, because they're confident that they know the equipment well enough not only to trust it, but also to identify and handle any problems.

Awesome answer. I really appreciate that you also had the personal experience of using automated nav aid identification during a check ride. Thanks!

I always ID by audio because I love morse code

I've wondered the same thing with the Garmin G1000 glass cockpit as it has the same functionality as the 430 - it processes the audio morse code signal usually filtered using the ID button on a regular NAVCOM to see if the character code is present. It cannot, however, process a non-morse audio identifier such as a recorded voice and you'll have to listen if it doesn't identify and display the NAVAID's 3-letter identifier automatically. Published recommendations for positive navaid identification are in the FAA Pilot's Handbook of Aeronautical Knowledge Chapter 15, page 23 Link Here, and I'm certain in some other places as well (probably the FAA AIM). I will certainly be listening to the morse code just to verify - when flying IFR in IMC (instrument meteorological conditions) your life is on the line. If it's a clear VFR day and you know the route and you definitely know where you are and you're using the NAVAID just for reference to keep a straight course, then maybe not, but in any other situation I'd be listening and checking the morse code or voice recording against my sectional/chart.


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Are there any runways that aren't labeled reciprocally to each other?
Runways are generally labeled by their magnetic azimuth between 01 and 36. This means that runways are normally labeled on each end with a number that is reciprocal to the other by 180 degrees.
Do any runways exist where the approach ends aren't labeled reciprocally to each other?

"Magnetic variation, however, can have a considerable impact near the poles." but it is of course the same at both ends, unless you want to count thousandths of one degree ;).  I'm not sure what you are asking since, as runways are straight, one end must be 180 degrees opposed to the other.

@Simon If you have a runway crossing the North pole, you would have to number both ends with 36 don't you? ;-)

On this question there are some examples of runways that are only labeled at one end

Unless the runway crosses the pole as @DeltaLima says, there isn't going to be enough magnetic variation over the course of a 8000 foot runway to change the numbering. Even if the variation was enough to cause a single digit change, I doubt it would happen as the pilot wouldn't account for the variation change that close to the airport anyway. I've seen signs at some airports that warn about the variation or a disturbance as much as 10 degrees, but it didn't affect numbering.

"The pole" isn't an exact point, and there is a very large area of "magnetic unreliability" where you could have just about any reading....

does this count? http://www.endlessrunway-project.eu/

@Lnafziger: Well, runways are numbered with respect to true north in the area of magnetic unreliability, so if that area happened to include the geographical pole...

Elk City, ID has runway 14/35 with about 30 degrees between reciprocal approach paths:

Elk City was the first one that popped into my head too! Of course, the physical runway surface is not actually labelled. Fun strip!

No, but at airports with multiple, parallel runways they will use an adjacent runway heading.
Example: KATL, Hartsfield Jackson Intl, in Atlanta, GA, which has five east-west parallel runways designates them Runways 8L-26R, 8R-26L, 9L-27R, 9R-27R, and 10-28.


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Propulsion method for MANPADS missiles
What propulsion method is used for small short range handheld missile systems? Liquid fuel rocket engines are the gold standard but I suspect require too many components for the size requirements.
Is it solid fuel rockets or is there some other method? Looking at the outside it doesn't look like they have a turbine or air intake.

In order not to burn operator the missile must accelerate to (or close to) cruise speed before the tail leaves the tube. Only a solid booster can burn this fast. Had you picked another propulsion, then the missile must a two-stage.

Missiles like a LAWS or Stinger use solid rocket motors.
Despite liquid fuel being preferred for space launchers, for a MANPADS type missile the combination of storability, inertness in transport, low toxicity, and near-zero setup time, along with the very limited performance requirement (compared to longer range missiles) make solid propellant virtually universal.
Don't forget, these missiles are closer, size, weight and performance wise, to a High Power model rocket than to even an SRBM -- and much larger missiles (like the long-running Sidewinder) use solid propellant for the same reasons.  Unlike models, however, these missiles are steerable -- various ones either have seeker heads (like the Sidewinder, too large for shoulder launching, but still solid propellant and small by missile standards), or are wire or radio guided.  Steering is accomplished either aerodynamically, with movable fins (like the Sidewinder), or by thrust vectoring with either a gimballed nozzle or jet vanes (the last is technology that goes back to the 1940s on the A-4 and Wasserfall).
While solid propellant rockets aren't practical to throttle, missiles typically don't care beyond a timed thrust profile to facilitate operator safety -- typically "big push to exit launcher, short idle to provide standoff from the operator, then cruise thrust".  They're then expected to remain under near constant thrust until warhead detonation (or self destruction on a miss).
Some, of course, like an RPG, or WWII bazooka, aren't steered at all; rather, they're aimed like a gun.
Liquid fuels that can be stored and launched on short notice are very toxic (hydrazine derivatives and nitrogen oxides, either of which will kill you quickly).  Those that are less toxic require much more infrastructure, as they almost universally use liquid oxygen (which has to be kept a lot colder than dry ice), and that has to be filled immediately before launch -- and has its own hazards.

Thanks, that makes sense. One thing though, my understanding is that solid rocket engines do not allow for thrust control, it seems like this would be a problem.

Throttling, no, vectoring, yes, via gimbaled nozzle or jet vanes.  I'll edit in.

You can put steering vanes right behind the nozzle in the exhaust flow and it wouldn't matter if it was a solid rocket motor.  The V2 was steered that way.

@JohnK Yep, 3rd paragraph, "A-4 and Wasserfall" -- V-2 was the Allied propaganda name for the A-4.  Redstone used the same method as A-4 -- jet vanes coupled with movable fin sections.

Ah yes that's right.  I wasn't paying attention.

@FourierFlux Partially true. While solid rocket motors can't be throttled in flight, the thrust profile over time can be controlled by changing how the propellant is arranged inside the combustion chamber during production.

The main reason to use solid rocket motors is storage. These things are (and must be) designed to sit on shelves for years and then must function at the press of a button. Reading Ignition! will tell you how hard this would be with liquid rocket fuel.

That’s a great book for sure, @PeterKämpf. And on the subject of thrust control, missiles at this range don’t need much thrust level control besides “go” once they’re out of the launcher and a safe distance away, and the low altitude gives multiple options for steering.

@FourierFlux: FYI, Joe Barnard of BPS.Space just did a video on throttling of solid (model) rocket motors: https://youtu.be/8sksiYfkses In the video, he also mentions some additional mechanisms to the one he his presenting that work, but not on the small scale of a model rocket (and the small budget of an amateur rocketeer).

@JörgWMittag I've seen that video, hence "aren't practical" vs. "impossible" in my answer above.  And as noted, for small missiles, all that's really needed is a high-low-cruise thrust profile which can be shaped into the propellant grain.

Another, unusual way to steer, is to have rows of charges along the body of the missile, directing some of their thrust sideways. By sequencing which charges on which side of the missile are fired, it can be steered. When it flies it makes a sound like Pop, Pop, Pop, Pop, ..., as each charge goes off.

@GlenYates And if you steer too wildly, you lose the ability to steer in that plane.  Seems I've seen demos of this in development for kinetic kill antimissile and antisatellite missiles, don't know of it ever being even proposed for environments where fins can do the job.

@ZeissIkon Yet this was the method used by the FGM-47 Dragon ATGM. It was retired from US service in 2001, but is still in use by several countries.

@GlenYates Seeker head, rather than operator steered, I'm guessing.

One thing missing from this answer, is that many systems use compressed gas to throw the missile 20m or so from the launcher before the engine is ignited. This protects the operator from the exhaust if launched from a confined space and helps to prevent giving the operators exact location away.

@GlenYates That isn't really directly answering the question -- those missiles still use solid propellant rocket motors.

An explosion (say from a grenade or bomb), @GlenYates, isn't going to care too much about missing by 20m. Grenades, maybe, but if the targeted fighter has a chance to pop off one missile or bomb and gets within 20 meters, it's curtains for the guy who launched from the ground.

To add to the earlier answers Juan Browne recently posted a video on YouTube in which he explains that the Javelin Anti Tank Missile uses a two stage solid rocket motor. One is for launch and the second for flight and the two phases of flight are clearly visible: Javelin Overview video

Why would you even want to throttle such a missile?  The missile has to be able to stand up to the thrust of the first stage (burns very quickly so it's done by the time the missile leaves the tube), there's no reason to use a lower acceleration for the second stage.  Once the booster is spent it coasts until either it hits it's target or decides it has failed and self-destructs.

Most shoulder-fired missiles, whether anti-tank or anti-aircraft, are actually two-stage rockets. The first stage is a very fast-burning motor, designed to burn out before the missile exits the launch tube. There is then a short delay, designed to get the missile some distance away from the launcher before the much larger main stage motor fires. The back-blast from a main motor can be 15-20 feet, definitely not healthy for the operator. High speed video of a launch will show the missile popping out and maybe even dropping a foot or two vertically before the main stage fires.


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According to ATFM terminology, when is a aircraft on the runway?
I am currently working trial writing a program capable of determining where a given aircraft is based on ATFM timestamps. My aviation background is pretty limited as I am only a mere IT developer.
When is an aircraft on the runway? Of course when it lands, and when it's about to take off, but there do not seem to be timestamps that indicate this?
Well the first one, the landing on to a runway seem to be covered by ALDT.
But when it's on the runway for taking off? ATOT? Is the aircraft not airborne at that point?
How do I using the ATFM timestamps determine when an aircraft is on the runway ready to take off?
Per a comment: AFTM is Air Traffic Flow Management, ALDT is aircraft landing time and ATOT is aircraft takeoff time.

I don't think that ATFM timestamps have the level of detail you'd need to determine when an airplane is on the runway. Why are you using this approach?

@Carlton Banks There are yellow "stop" stripes at the end of the taxiway where it meets the runway, some distance short (like fifty or a hundred feet or so) and when you cross the stripes you are, legally speaking, on the runway.  You would have to be able to resolve aircraft position at the point of the timestamp as being on one side or the other of the stop stripes.  The only source I'd think you could find that sort of data would be archived Air Traffic Control Ground Radar data, if archived date is available.  I would contact the FAA to find out if that sort of data exists.

Can you help us mere pilots by defining your acronyms?

AFTM is Air Traffic Flow Management, ALDT is aircraft landing time and ATOT is aircraft takeoff time.


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Approximately what percentage of aircraft are equipped with RNAV?
I was hoping someone could provide me with an estimate of what percentage of aircraft are equipped for RNAV (Area Navigation). I'm more interested in commercial aircraft, but business and general aviation would be nice to know too.
This is for my own curiosity, so speculation is perfectly fine.

It's probably close to 100% in commercial aircraft, at least for practical purposes: RNAV is a broad term and in many contexts it's informally used to mean GPS, even if that isn't really correct. For example, GPS instrument approach plates are titled "RNAV (GPS)".

Which part of the world are you interested in?

I guess if I had to choose it would be the U.S. And Europe.

Use of RNAV began in late 1960’s . Some airlines began exploring RNAV systems

KLM/SwissAir/SAS/UTA had a cooperative effort
Swissair became responsible for the development of a database to
support this effort

In June 1973, National Air DC-10 equipped with Collins ANS-70 conducted RNAV operation, including approaches in VMC, with database.
In January 1983, the Federal Aviation Administration revoked all RNAV routes in the contiguous United States due to findings that aircraft were using inertial navigation systems rather than the ground-based beacons, and so cost-benefit analysis was not in favor of maintaining the RNAV routes system.
RNAV was reintroduced after the large-scale introduction of satellite navigation.And, since 1990 it is there in almost all the planes you see.
So, as a rough estimate it would be more than 90%. Because, most of the pre-1990 planes have either been upgraded or grounded.
Sources: Wikipedia, Federal Register, This Article.

To The downvoter please explain your reason, so that I can improve

So when you say satellite navigation, that's doesn't mean ADS-B right?

@David: Satellite navigation means GPS. ADS-B is not a navigation, it is a system for reporting position via radio. And note, that pre-2000 GPS with the ~100m error (selective availability) was completely sufficient for en-route navigation (though obviously not for approaches).

No I don't mean ADS-B. It was not even in air near the 90's!

Alright thanks everyone :)


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Why is it appropriate to announce ‘stable’ on final approach?
I have recently discovered that a budget airlines flight deck in the UK (Airbus 320) announce ‘Stable’ on the final approach. Both the Captain and F.O, just after 500 ft is called out by the computer.
It does seem obvious and yes, the word does speak for itself, but why does it need to be verbally announced?
Is it similar to the same reason when ‘Thrust set’ is announced? To acknowledge that they are happy with the appropriate aircraft instruments and performance, and that it is ‘stable’ and safe to land? I know ‘hundred above’ is a great way to warn the crew that minimum is coming very soon so does stable lead them into this ‘is the aircraft able to proceed’? If one was to not agree that it was ‘stable’, not quite sure what that means at this stage, it does not leave them much room for negotiation does it? Aside from the obvious, what could make one pilot disagree with ‘stable’?

The FAA offers some advice on this:

An unstable approach is simply an approach that does not meet the
  criteria for a stable approach established by the aircraft operator.
  As an illustration, Flight Safety Foundation defines a stable approach
  in the following terms:
On the correct flight path:

ILS Approach - ILS within 1 dot of the localizer and glide slope.
Visual Approach - Wings level at 500 feet AGL.
Circling Approach - Wings level at 300 feet AGL.
Only small heading and pitch changes required.
Speed within +20/-0 kts of reference speed.
Aircraft must be in proper landing configuration.
Maximum sink rate of 1,000' per minute.
Appropriate power settings applied.
Briefing and checklists complete.
During IMC - Stable by 1,000 feet AGL.
During VMC - Stable by 500 feet AGL.

If the approach is not stable by 1,000 feet AGL or 500 feet AGL
  (depending on weather conditions), or if the approach becomes unstable
  below these altitudes, the pilot should initiate a missed approach/go
  around. The pilot may initiate a go around at any time above or below
  these altitudes if deemed necessary. It is possible for a pilot to
  initiate a go around even after touchdown on the runway, but not after
  the thrust reversers have been deployed.

They are simply verbally verifying the approach is stable and they don't feel they need to go around. I would think Various OpSpecs dictate how go-arounds are initiated but in reality either pilot can initiate a go-around.  If an approach is unstable a go-around should be initiated.
IATA advises that callouts are used which may be why carriers are adopting them.

Furthermore, the adoption of calls of “STABILIZED”, “UNSTABLE” or
  “GO-AROUND” at a given point on the approach (stabilization
  altitude/height for example) may improve decision making and
  compliance to ensure a timely go-around is carried out. While a
  “STABILIZED” callout might be required at either 1,000 feet or 500
  feet above touchdown, the “GO-AROUND” command can and must be made at
  any time prior to deployment of thrust reversers. Once again, if such
  callouts are adopted it is essential that an acknowledgement is made
  by the other pilot in every case


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What’s the difference between an AIRSPEED LOW warning and a STALL warning?
Just an enthusiast here; pardon the dumb question. Im a little confused between the difference of a stall and airspeed low.

“An aircraft Stall Warning System is that system which provides the pilot with advance warning of an impending stall.”

A stall occurs when the wings are not able to produce sufficient lift, and therefore, the aircraft will begin to drop.
‘Airspeed Low’ is telling the pilots that you have very low airspeed but if the airspeed is too low, won’t the plane then stall?
What’s the difference then between AIRSPEED LOW warning and a STALL warning? For they both lead to the same result. An aircraft that stops flying and starts falling. Is one more advanced of the other, perhaps? If you get an AIRSPEED LOW warning do you have more time to recover than if you receive a STALL warning? If that’s the case, they both take the amount of time to recover, though. Max thrust and point the nose down.
Do you perform difference actions for these two warnings?

What aircraft produces these warnings?

doesn’t all airbus fleet? apologies, added the tag…anyway, the 330 definitely does….

@Organic Marble, most current day Boeings.

@cmp, are you sure it is an Airbus warning at all? As far as I remember, Airbus only gives you a “SPEED! SPEED! SPEED” aural warning and then you hit the alpha-min, alpha-floor and alpha-limit, which won't let you proceed to STALL unless in alternate mode. Also the fact skipper44 answers for Boeing suggests it isn't in Airbus, because the low-speed and auto-thrust logics are different between Airbus and Boeing.

Related for Airbuses. This is A320 specifically but other have similar function.
https://aviation.stackexchange.com/questions/66646/what-is-the-difference-between-low-energy-warning-and-alpha-floor-in-a320

Referring to one manufacturer's nomenclature and systems:
The "AIRSPEED LOW" caution occurs shortly after the speed drops below the Minimum maneuver speed. The Min Maneuv spd is ~30% above stalling speed for slat/flap config. Even if the auto-throttle is not engaged in any mode, as long as the auto-throttle is armed, this is the speed at which "auto-throttle wake-up" takes place, ie the auto-throttle pushes the thrust levers up so as to regain speed without any pilot action. At typical weights and maneuvering speeds this will occur well above the speed at which stick-shaker (stall warning) takes place.
Immediate action is to be taken by the pilot when "AIRSPEED LOW" is displayed. It is considered that the airplane is entering the 'approach to stall' phase. Here's an actual extract (maybe not the latest though)

The first indication of an approach to stall is the AIRSPEED LOW EICAS
message. A stall warning should be readily identifiable by the pilot,
either by an artificial indication (stick shaker) or natural
indication (initial buffet). During the initial stages of a stall,
local airflow separation results in buffeting, giving a natural
warning of an approach to stall. Stick shaker operation will usually
precede initial buffet as a stall warning indication. In some cases,
near cruise altitude and cruise Mach, stick shaker may be simultaneous
with initial buffet. Recovery from an approach to stall should be
initiated at the earliest recognizable stall warning, either AIRSPEED
LOW EICAS message, stick shaker or initial buffet.

Thus the procedure is the same for both the AIRSPEED LOW and SS and it is called, "Approach to stall or stall recovery". Here are the first few steps only:

Pilot Flying:
Initiate the recovery:

Smoothly apply nose down elevator to reduce the angle of attack until buffet or stick shaker stops.

Continue the recovery:

Roll in the shortest direction to wings    level if needed
Advance thrust levers as needed
Retract the speedbrakes
etc

note 1. When the AIRSPEED LOW caution first appears, there would be no SS and if there's no adverse bank, the first action would be to advance thrust levers.
note 2. The procedure quoted by @cmp -  If that’s the case, they both take the amount of time to recover, though. Max thrust and point the nose down - has now been changed. The increase in thrust is to be made after this initial procedure of reducing the AoA and leveling wings. This is based on the consensus between industry, regulator, professional pilot's groups etc., who made the study of the altitude loss/ ground contact issues during LOC-I (Loss of Control - Inflight) study.
Actual procedures must nevertheless be checked for the aircraft type being flown and as the actual situation may demand, for e.g. 'ground contact is a factor'.

So the issue is not only threat of a stall but not having enough air over the tail surfaces for a turn or some other movement from level flight?

This is an interesting answer, although clearly not applicable in the GA aircraft I fly.  Can someone scope this answer? Are the features described common to all transport category aircraft?

@MacGuffin, no, it's still about the wing, mainly. When you turn, the centripetal force is also provided by wings by banking into the turn, but that means the wings need to produce more lift in a turn and therefore the stall speed increases.

@MacGuffin, there is also minimum control speed, which is minimum speed when rudder has enough airflow over it to compensate for one engine running at maximum power while the other being shut down, but that does not depend on flap setting and this warning does, so this warning is just about margin above stall to allow turning.

@JanHudec  I recall some kind of minimum speed for 2-engine propeller planes to maintain controlled flight.  The speed was different depending on which engine was out if both props spun the same direction.  I thought there might be something similar with jets, just without the speed being different depending on which engine is out.  This adds another element, thanks.

Hi @2NinerRomeo, you may find these 2 documents to be informative: 1. https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_120-109A_CHG_1.pdf  2. http://www.tc.faa.gov/its/worldpac/techrpt/rd77-26.pdf (I'm not sure if there's a newer version of doc 2.)

@MacGuffin that's the minimum control speed I mentioned, and it applies to all multi-engine aircraft, except jets don't have P-factor, so both sides are equally critical. It however tends to be less of an issue in jets due to their higher performance, less drag of the dead engine, and the engines being a bit closer to the fuselage. I don't recall asymmetric thrust handling being a factor in any jet crash, but I recall it being important factor in at least a few turboprop crashes.

@Jan_Hudec, On atleast 2 types of very popular large jets of the day, controllability issues have necessitated a minimum take-off weight incase of full power take-off and also higher approach speeds than expected at LOW landing weights.

From a physics point of view (which may or may not agree with manufacturers’ terminology) a stall is when the angle of attack is steep enough that the airflow breaks away from the upper surface of the wing.  Low airspeed is just what you would expect.  In level flight at a known air pressure the relation between these two is well understood, but in other conditions this relationship can break down; a radical manoeuvre could induce a stall at relatively high speed, whereas a wing with zero airspeed will never be stalled.  So both warnings inform the pilot, and hopefully they can interpret the information appropriately.


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How can you tell what position the flaps are in whilst on a commercial aircraft?
I am flying with thomson soon and want to be able to tell what position the flaps are in. How can i figure this out?

I thought that there was different positions for flaps? e.g. 1,2,3,4

@L.Halfpenny sure, different aircraft number it different though, with different visual effects as well. And to see anything you need to be seated in just the right place or you can't see the flaps at all.

Launch a flight simulator with a quality addon for the aircraft in question. 2. Set the flaps and remember the appearance in the simulator. 3. Compare with observed visual.

@L.Halfpenny indeed there are, but the difference is usually quite noticeable on most airframes. The common settings are cruise (retracted), takeoff and landing. Slightly less common are variations on those, like climb (a bit less extended that take-off) or short-field landing (on aircraft that sometimes operate on unusually short or improvised airfields)

See also the answers to https://aviation.stackexchange.com/questions/39634/what-does-this-black-triangle-placard-on-board-an-a320-denote

If you are seated behind the wings, but close, you can usually see black markings (thick line and a number) near the inboard side of the engine pylon which indicate their extension. Some might not be visible when the wing is in cruise configuration.
Same goes for leading edge slats, only you'd need to be seated near the overwing emergency exit to see those.
I've personally seen them on both Airbus and Embraer jets (no recent flights on Boeing airframes so can't confirm if they mark them too).
(Source)

bombardier doesn't have markings

I think Embraer has consecutive numbers and not degrees.

FWIW, I don't recall ever seeing these markings on a Boeing aircraft.

@reirab: Me either.